The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Hearing-impaired people who cannot hear voices and sounds due to congenital or postnatal loss of the sense of hearing are exposed to various inconveniences and dangers because they cannot hear sounds in daily life. In particular, as vehicles are popularized and more hearing-impaired people drive vehicles. However, hearing-impaired people have to recognize all surrounding situations simply only through the sense of sight while driving, so they are more easily exposed to traffic accidents and safety accidents more than non-hearing-impaired people.
In general, a horn sound and a warning sound are used to let other people to know an emergency situation or a warning situation in driving. Accordingly, drivers can recognize the surrounding situations through a horn sound and a warning sound from other vehicles and can avoid traffic accidents. As sound signals that are generated when vehicles are driven, there are sirens of an ambulance, a fire engine, a police car, and a tow truck, sound by a collision and sudden braking, and the warning sound of a railway cross gate, and drivers can immediately recognize surrounding situations and start defensive driving upon hearing these sound signals.
However, hearing-impaired people cannot hear sound signals that are frequently generated such as a horn sound and have to only visually recognize all surrounding situations when they drive, so they easily feel tired due to excessive nervousness. Further, they recognize a warning late and cannot quickly take appropriate measures, which causes traffic accidents in many cases.